Some of the work demonstrates promise, but constructing anycompany logos like this is really only software practice, not design practice. Design must have a specific premise, a purpose, a problem to solve, a message to convey. Brand design begins with a company mission and subsequently factors in research of the product(s), the competition, the martket, the applications, etc. All you’re really doing with these is scribbling for the sake of scribbling. Not entirely a waste of time, but not graphic design.

It’s not incredibly difficult to dream up fictional companies and products for exercises like this. It’s good for your creative muscles and lays the necessary contextual foundation for your design. I’d advise you to at least start practicing that way.